US-led forces have subdued the rebel stronghold of Samarra in two days of fighting, the first of a series of military steps expected in coming weeks designed to seize control of insurgent cities and pave the way for January elections.

But the relative ease of the Samarra operation - in which a 5,000-strong joint US-Iraqi force launched one of the largest coalition strikes since the 2003 US invasion of Iraq - belies a risky strategy that will rely on freshly trained and untested Iraqi forces for success, analysts say.

The inexperience of those units, which will be responsible for long-term security after the cities are retaken, is one reason that much tougher ground elements of the offensive, against Ramadi and Fallujah, are expected to wait until November - after the US presidential election and to give Iraqis more training time.

But a wave of increasingly lethal attacks by insurgents has killed hundreds of Iraqis in recent weeks, which may be prompting earlier moves on softer targets like Samarra.

"This is about getting control of the country ahead of elections, but what worries me is: What type of control? And how sustainable is it?" asks Toby Dodge, an Iraq expert at the International Institute of Strategic Studies in London. "You are going to garrison Samarra, put troops on the ground and police it, and bring in indigenous forces," says Mr. Dodge. "We know from the past that the police aren't very good at imposing political order. And the National Guard - which everyone in the Green Zone [where US and Iraqi leaders reside] invests a lot of hope in - is penetrated from top to bottom by [insurgents]."

US forces Sunday controlled much of Samarra, 60 miles north of Baghdad. The US military says it killed 125 insurgents and captured 88 more; residents say many civilians are among the dead. Rebels marched openly in Samarra last week with banners of Tawhid and Jihad, the group led by Abu Musab al-Zarqawi that has claimed numerous car bombs, attacks, and the capture and killing of foreign hostages.

The Associated Press quoted one grateful local resident. "The city has been living in a state of lawlessness," said Abbas Mahmoud. "I hope that after this operation, law and order will be restored." But many others in Samarra criticized the number of civilian casualties.

The AP also quoted US officers praising Iraqi troops, numbering 2,000 in the weekend offensive. "The more operations they conduct, the more confidence they will gain, and the better they will perform," a US military spokesman in Samarra said Saturday.

The shift to US-led military offensives - which indicate that US and Iraqi officials see few other options - was also evident in Fallujah, 25 miles west of Baghdad. Weeks of airstrikes continued against targets the US says are linked to Mr. Zarqawi's network.

Doctors reported two civilians killed in a US airstrike on Fallujah overnight Saturday; two more were killed when a tank fired at a house. The US military said the airstrike hit a weapons depot that "reduced the capability of the Zarqawi network," killing up to 15 rebels and sparking 45 minutes of secondary explosions. The night before, it said a "precision strike" killed up to 20 insurgents who were training; video footage showed a child being taken from rubble.

Already 18 months into the US occupation, Iraqis say they don't understand why the insurgency continues to spread or why the 138,000-strong US presence has yet to bring security. UN Secretary General Kofi Annan said that credible elections will not be possible under current conditions. US officials and Iraqi Prime Minister Iyad Allawi have said that elections may take place only in stable parts of the country.

Such concern is what is driving plans by the interim Iraqi government to reverse its approach to insurgent strongholds, mostly in the Sunni triangle that stretches north and west of Baghdad, which have turned into no-go areas for US and Iraqi forces.

"Allawi's preferred tactic was to negotiate and bring [insurgents] in," says Judith Yaphe, an Iraq expert at the National Defense University in Washington. "If they are determined to do as much damage as possible, and there is nothing you can do to convince them, where do you go?

"You reach a point where you're either going to have to move forward or move out," she says.

But launching such a widespread offensive may have uncertain results and require tough decisions by US commanders. While Samarra may have been subdued this weekend, tougher cases in the past have not always yielded to military pressure.

US marines last April, for example, were ordered to root insurgents out of Fallujah. After some 600 Iraqis and about a hundred marines were killed, commanders decided, in the words of one senior intelligence officer at the time, that "destroying a city to save it is not an option." Insurgent activity returned not long after; the "Fallujah Brigades" created by the Marines have since been disbanded.

"A heavily armed fist is not the right tactic to solve these problems," says Saad Jawad, a political scientist at Baghdad University. "Even if they succeed militarily, the problem will still be there. What are they going to do with the [negative public] opinion of the people?"

Several senior Iraqi officials are from Samarra and could have begun talks to "come to terms" with a peaceful solution, says Mr. Jawad. "But using arms, killing [so many] every day, this is not a solution. This is another mass grave. If Iraqi blood is so cheap, then why did [the US] come to Iraq? They could have left it to Saddam Hussein," he says.

"There will be a lot of criticism," says Yaphe of the fallout from collateral damage. The offensive is "high risk," she says, because insurgents are so intermingled with civilians.

"It's difficult to make these surgical strikes - one hopes to do that, but there is no such thing," adds Yaphe. "Part of the strategy has long been, [get insurgents] where you find them. At this point, we're not going to ask questions."